Process for wood preservation



Patented July 8, 1930 UNITED STATES PA ENT OFFICE- vrc'ron a. ABRAMS, or nmmswrciz, enonem, ASSIGNQR or ONE-HALE T n01.19311.- SHELANDER, or BRUNSWICK, GEORGIA No Drawing.

- The present invention relates tothe pres ervation of wood, and has particular refer-I ence to treating wood in the form of piling, timbers, railroad ties, planks and the like,

5 which are to come into contact with sea water, for preventing the destruction caused by ma-' rine insects such as Teredo, Limnoria and the like. I

I desire to call-attention to-the fact that wood, for piling and for other uses in which. it is permanently or temporarily in contact with sea water, is subject to attacks by various forms'of animal life, such as the Teredo and Limnoria, barnaclesand various others,

which borefinto the wood, thereby weaken ing; the wood,-and greatly shortening the life of the wood under these conditions. Also in some locations, animals such as termites eat into wood which is not in contact with 0 sea water, such as railroad ties, sills ofbuild- I ings or houses, door steps and the like, this beingparticularlynoticeable in the case of wood which is close to the ground or on the ground, and which is accordingly more or less damp. In some localities, particularly in the south, railroad ties are frequently in jured in this manner.

In accordance with the present invention, 1 preferably treat the wood first with a solu- 39 tion of copper sulphate, byimpregnation,

after which the excess of copper sulphate solution which has not been absorbed is removedfrom the wood, or from the treating vesse1,.and then the wood is impregnated with a solution of a soluble resinate, whereby a. an insoluble copper resinate is formed. In

some cases more than two successive treatments with these two substances alternately may be employed, and it will be understood 40 that the copper salt or the resinatecan be applied first as desired, and the invention is not restricted to any particular order of treatment with these two materials. 1 When the wood is in a green or wet condition, it may first be steamed and subjected to a vacuum, in order to dry the wood and to open the pores thereof. When the wood is dry, it may first be subjected to a vacuum in order to drive out the air from the pores of the wood, as much as possible.

Application filed November 19, 1927. Serial No. 234,566.

Assuming the woed to. be in an air tight. cylinder or vessel under vacuum, for the purpose ofwithdrawing the air from the pores of the wood, in which operation a vacuum of say 18 to 25 inches more or less, may be em- 'pl'oyed, depending upon the conditions, and

the Wood. may be hot or cold as desired, there is then introduced into the said receptacle, a solution of a rosin soap. This solution may be a 5% solution of sodium resinate, al-

thoughstronger or Weaker solutions can be used if desired. The solution is run in preferably sufliciently to completely submerge the wood, after-Which fluid pressure is applied, say by pumping in more of" the sodium 5 resinate solution, in order to cause the Wood to become permeated withthe sodium resinate solution. When sufficient impregnation has been produced, the pumping will be stopped and the unabsorbed liquid is pumped out of thetreating receptacle into a storage tank. Steaming and, or, a vacuum is preferably applied at this stage, in order to draw out vmore or less of the resinate solution, which is likewise-pumped into the storage tanks. An aqueous solution of a soluble copper salt,

such as copper sulphate, say 2 to 10% strength, is then pumped in, and pressure is then applied upon the solution to force the copp r sulphate solution into the wood, prefo erably sufficiently to thoroughly permeate the wood. The copper sulphate reacts with the sodium resinate in the wood, to produce insoluble copper resinate, and-after sulficient impregnation with the copper sulphate solus5 tion,-the'excess is drawn. ofl", and the wood 1 may then be considered as completely treated, and may be dried either by steam and vacuum, or by merely stacking up the wood in the atmosphere or under a shed. Generally I recommend continuing the operation,

by giving a second treatment with the rosin soap solution, similarly to the above, in order lution of a soluble copper salt, but for ordi- 10 properties of the copper compounds also lprenary purposes two, three or four treatments, will be found to give a suficient impregnation.

As a modification of the invention, I may employ in the first step, say a solution of a resinate, then a solution of copper sulphate, and then a solution of ordinary soap (for example a soap made from caustic. soda and tallow or other form of grease); Instead of using resinate solution alone, I may employ mixtures of rosin. with various .oils and greases for producing the initial soap.

I have above referred to the use of copper salts such as copper sulphate. ever within the scope of the invention, to employ salts of other inetals having toxic properties' or insect destroying properties, such as arsenic, tin, zinc, mercury and-the like.

It will be furtherunderstood that in some instances it may be advisable to employ a solution-of a soluble resinate, then say a copper salt, then a soluble carbonate or -hydroxide, which react with the excess of copper, producing a mixed precipitant in situ of the wood.

The process presents certain advantages over the prior processes of using creosote oil, heavy petroleum oil and the like, in that the preservation seems to be more permanent, and the materials used are much cheap- 'er than creosote and similar substances. Wood impregnated with creosote is also objectionable as having a disagreeable odor, and also because the active constituents of the creosote. seem to be sufiiciently soluble to be It is how- I claim 1. A process of preserving wood 1n the form of piling, timbers, railroad ties, planks,

and the like, which comprisesqthe step'of forming copper resinate in situ in the pores of the wood.

2. A process of preserving wood in the form of piling, timbers, railroad ties, planks, and the like, which comprises the step of forming copper resinate throughout substantially the entire body-of the wood, thedeposit of copper resinate beingl more concentrated' in the outer parts of t e pieces of wood.

3. In the preservation of wood in the form of structural articles the steps of alternately impregnating the wood with a soluble copper salt and a soluble resinate separately introduced into the pores of the wood, whereby an insoluble copper resinate is formed in situ in the cavities of the wood.

4. A process of preserving wood by the alternate impregnation with solution of soluble soaps and with an aqueous solution of soluble copper compounds separately intro-' In testimony whereof I aflix my signature.

'VIOTOR R. ABRAMS.

leached out of the wood, in water, after a time. 7

I call attention to the fact that the impregnation may be carried to any depth as desired, and inordinary practice, it is possible to car- 'ry the impregnating solution clear to the heart of the timber. Inordin'ary practice there will be much more of the copper resinate, etc., precipitated in the outer portions of the wood, than in the inner portions, which is really an advantage because the insects and other organisms have to enter the wood from the exterior. When planking, boards and other sawed timber is to be employed, it is preferably treated after sawing, in order to produce the said. effect.

I call attention to the fact that the toxic vent the action of fungi, spores and teria which produce decay. v

The invention also contemplates the alter- .nate impregnation of the wood with solutions of soluble soaps and with soluble salts of the heavy metals other than sodium, potassium, lithium, calcium,'.and ammoni Also I may employ solutions of ordinary soaps, such as the oleates, stearate's, linoleate's rhionqleates, tungoleates and other a fatty oils entirely to replace the resinate solu- "tions in the manner describedabove. 

